Machine-type communication (MTC), also known as Machine-to-Machine (M2M) communication, is a form of data communication which involves one or more entities that do not necessarily need human interaction. Such communication may be facilitated by the data services offered by existing mobile communication networks. However, a service optimised for machine-type communications differs from a service optimised for human-to-human communications. In particular, machine-type communications are different to current mobile network communication services as they involve different market scenarios, data communications, lower costs and effort, and a potentially very large number of communicating terminals with, to a large extent, little traffic per terminal. The entities involved in MTC are referred to as MTC Devices and MTC Servers. A MTC Device is a communication device equipped for MTC, which communicates through a PLMN with MTC Servers and/or other MTC Devices. FIG. 1 illustrates schematically a communication scenario in which MTC Devices communicate with an MTC Server over a telecommunications network.
The 3rd Generation Partnership Project (3GPP) is currently working to define a comprehensive set of network improvements for MTC. As part of this work some general requirements (e.g. in the areas of identification, addressing, congestion control etc) have already been defined. In addition, some network functions that are required in order to optimise networks for use by M2M applications have been identified, with these network optimisations being referred to as MTC Features. 3GPP TS 22.368 v10.1.0 defines these MTC Features as including Low Mobility, Time Controlled, Time Tolerant, Packet Switched (PS) Only, Small Data Transmissions, Mobile Originated Only, Infrequent Mobile Terminated, MTC Monitoring, Priority Alarm Messages, Secure Connection, Location Specific Trigger, Network Provided Destination for Uplink Data, Infrequent Transmission and Group Based MTC Features. It is expected that network operators will be able to independently offer MTC Features to a MTC Subscriber, with the MTC Features provided to a particular subscriber being identified in the subscription. As such, the MTC Devices that belong to a given MTC Subscriber will be controlled by the subscription and therefore subject to Subscription Control. However, it is not yet defined in any detail as to how Subscription Control of the MTC Features will be handled.
Currently, subscription data management for traditional mobile services is carried out according to the procedures defined for the S6a, S6d, Gr, and D interfaces (see 3GPP TS 29.272 and 3GPP TS 29.002). In general, these consist of the procedures defined to update entities within the core network that are responsible for mobility management with the subscriber data stored in the HLR/HSS, either at the time of attachment to the network, at restoration, or when a subscription change occurs due to administrative procedures. However, these existing solutions only cover the procedures for updating the information regarding the subscribers subscribed services, and do not include how to manage subscription information that includes subscribed MTC Features. As such, there is a need to define procedures for management of subscription information that includes subscribed MTC Features.
In this regard, 3GPP TR 23.888 V0.5.1 identifies some key issues for MTC that require system improvements, and outlines solutions to some of these key issues. In particular, section 6.37 proposes two alternative solutions, referred to as Simple Subscription Control, which could be included in 3GPP Specification Release 10. The first of these solutions proposes doing nothing, provided that no MTC Features are included in Release 10. The second of these solutions proposes identifying the subscribed MTC Features as Information Elements (IEs) in the MTC Subscription stored in the HSS, together with some procedures to determine whether or not the subscribed MTC Features are supported by the MTC Device and by the network. In addition, according to this solution, all subscribed MTC Features are considered essential and mandatory such that, if an MTC Device or the network does not support one or more of the subscribed MTC Features, then an attempt by an MTC Device to attach to the network is rejected. However, the information that would be needed within the new Information Elements identifying the MTC Features, and the message exchanges that would be needed between the HSS/HLR and the core network nodes to control service and MTC Feature availability, are not specified.